Review Article

Drosophila melanogaster Models of Friedreich’s Ataxia

Table 3

Genetic modifiers of FRDA phenotypes in Drosophila.

ModifierPathwayEffect

Fer1HCH/Fer2LCH
(Co-expression)
Iron storageSuppressor of 
reduced life span [66], ERG, and photoreceptor neurodegeneration [45]

Fer3HCH (OE)Iron storage and oxidative stress protectionSuppressor of 
reduced life span [66] ERG, and photoreceptor neurodegeneration [45]

Irp-1A (RNAi) 
Irp-1B (RNAi) 
Irp-1B (LOF)
Iron sensorSuppressor of 
mild rough eye and impaired motor performance [82]

mfrn (RNAi)Mitochondrial iron importerSuppressor of 
reduced aconitase activity and IRP-1A and ferritin levels, impaired motor performance, and increased brain vacuolization [66]
mfrn (OE)Enhancer of 
locomotor defects and brain vacuolization 
[66]

Mvl (RNAi)Iron absorptionSuppressor of
mild rough eye and impaired motor performance [82]

Tsf1 (LOF) 
Tsf3 (RNAi)
Serum iron binding transport proteinsSuppressor of 
mild rough eye and impaired motor performance [82]

dZip42C.1 (RNAi) 
dZip42C.2 (RNAi) 
dZip88E (RNAi)
Zinc importer Suppressor of 
mild rough eye and impaired motor performance [82]

dZnT35C (RNAi)Zinc transporter to vesiclesSuppressor of 
mild rough eye and impaired motor performance [82]

dZnT41F (RNAi)Zinc homeostasisSuppressor of 
mild rough eye and impaired motor performance [82]

dZnT63C (RNAi)Zinc exporterSuppressor of 
mild rough eye and impaired motor performance [82]

foi (LOF)Zinc importerSuppressor of 
impaired motor performance [82]

Atox1 (RNAi)Copper chaperone donorSuppressor of 
mild rough eye and impaired motor performance [82]

dCutC (RNAi)Copper uptake and storageSuppressor of 
mild rough eye and impaired motor performance [82]

MTF-1 (OE)Metal responsive Transcription Factor Suppressor of 
impaired motor performance [82]
MTF-1 (LOF)Enhancer of 
impaired motor performance [82]

MtnA (RNAi)Heavy metal detoxificationSuppressor of 
mild rough eye and impaired motor performance [82]

MtnB (RNAi) 
MtnC (RNAi)
Heavy metal detoxificationSuppressor of 
mild rough eye [82]

Tsc1 (RNAi)TORC1 pathwayEnhancer of 
reduced survival [81]

S6K (DN)TORC1 pathwaySuppressor of 
impaired motor performance [81]
S6K (CA)Enhancer of 
reduced survival [81]

eIF-4E (LOF)TORC1 pathwaySuppressor of 
impaired motor performance [81]

Lrrk (RNAi)TORC1 pathwaySuppressor of
impaired motor performance [81]

Cat (OE) 
mCat (OE) 
mTPx (OE)
Antioxidant (hydrogen peroxide scavengers) Suppressor of 
reduced lifespan when overexpressed in the PNS [41]

dGLaz (OE)Antioxidant defenseSuppressor of 
reduced life span, impaired motor performance, aconitase inactivation, and lipid peroxidation [83]

Pdk1 (RNAi)Embryonic development (insulin receptor transduction pathway and apoptotic pathway)Suppressor of 
photoreceptor neurodegeneration [45]

Mef2 (RNAi)Muscle differentiationSuppressor of 
photoreceptor neurodegeneration [45]

lace (RNAi)Sphingosine biosynthesis pathwaySuppressor of 
photoreceptor neurodegeneration [45]

CA: constitutively active mutation; DN: dominant negative mutation; ERG: electroretinograms; LOF: loss-of-function mutation; OE: overexpression; RNAi: RNA interference.